Sure, and today middle-class Americans don't have to worry about food on a daily basis, but worldwide conditions have been dismal for most, if not all, of human

Sure, and today middle-class Americans don't have to worry about food on a daily basis, but worldwide conditions have been dismal for most, if not all, of humanity's history, and are just now getting better. For example, these rich cities frequently had to defend themselves against the poor and hungry. Being sacked was a common occurrence. It's a recent convenience (over the past few hundred years) that cities aren't surrounded by walls.